1. Field of the Invention
The present invention relates generally to the field of high speed data transfer, and more specifically to managing contiguously and virtually concatenated payloads in specific data transfer architectures, such as SONET/SDH.
2. Description of the Related Art
Data communication networks receive and transmit ever increasing amounts of data. Data is transmitted from an originator or requester through a network to a destination, such as a router, switching platform, other network, or application. Along this path may be multiple transfer points, such as hardware routers, that receive data typically in the form of packets or data frames. At each transfer point data must be routed to the next point in the network in a rapid and efficient manner.
Data transmission over fiber optics networks may conform to the SONET and/or SDH standards. SONET and SDH are a set of related standards for synchronous data transmission over fiber optic networks. SONET is short for Synchronous Optical NETwork and SDH is an acronym for Synchronous Digital Hierarchy. SONET is the United States version of the standard published by the American National Standards Institute (ANSI). SDH is the international version of the standard published by the International Telecommunications Union (ITU). As used herein, the SONET/SDH concepts are more fully detailed in various ANSI and ITU standards, including but not limited to the discussion of concatenated payloads, ITU-T G.707 2000, T1.105-2001 (draft), and T1.105.02-1995.
SONET/SDH may employ at least two different types of payloads called contiguously concatenated payloads and virtually concatenated payloads. The difficulty with employing both contiguously concatenated and virtually concatenated payloads is that multiple paths may be required to process data received in both formats. Two paths and/or two processors may typically be employed to address both types of payloads. Contiguously concatenated payloads may, for example, be provided on one path and processed with knowledge that only contiguously concatenated data is received, while virtually concatenated payloads may be processed on another path with similar knowledge about the payloads received. While separate pipelines and/or separate processors may enable systematic and straightforward processing, such a multiple path implementation tends to decrease throughput and is generally inefficient. Further, the data received may include payloads having odd sizes, such as sizes differing from the data path width of eight byte words. Receipt and processing of odd sized data requires expeding additional resources, which is undesirable.
A design that enables both contiguously concatenated payloads and virtually concatenated payloads to be processed irrespective of the type of payload received may provide increased throughput and other advantageous qualities over previously known designs, including designs employing the SONET/SDH architecture.